Various angle sensors are known in the prior art and typically comprise fluid filled electrolytic or capacitive devices such as clinometers or accelerometers. These sensors are particularly well adapted for calculating tilt angles but are also sensitive to cross axis rotation or acceleration.
The sensor of the present invention, with its pair of spaced, annular shaped, electrical resistance elements, has the advantage that the tilt angle of an object can be precisely measured without regard to the rotational angle of the object. In the drilling field, this is useful for maintaining a desired percent of grade in order to prevent re-boring. For instance, the angle sensor as described in the present invention could be used to measure the drill head pitch angle while the drill head rotates 360 degrees in roll.